Nearest neighbour considerations in Stillinger-Weber type potentials for diamond

Results of a preliminary investigation into the effect of varying the interaction cutoff on the bulk properties of diamond using a Stillinger-Weber (SW) type potential for C (Diamond) are presented. The interaction cutoff is varied over a range that includes and excludes the second-nearest neighbours. Whilst the original SW potential for silicon only included first-nearest neighbours inside the interaction cut-off, subsequent parameterizations for carbon (diamond) have also included second-nearest neighbours. Elastic and vibration properties of diamond were calculated over a range of cutoff distances used and the results show that certain lattice properties exhibit an approximately linear dependence on the interaction cut-off.